(This started off as a comment, but got too long.)
I'll be very interested to hear answers to this one - as I don't have an answer myself. There are other C# books I like (C# 3.0 in a Nutshell and Accelerated C# 2008) but they're not really introductory texts. I'm not as keen on Head First C# - although mostly on style grounds, now that the vast majority of the errors in earlier editions have been fixed. (If you're going to get it, make sure you get the latest edition.)
CLR via C# dovetails with C# in Depth in a different way, providing CLR details where C# in Depth provides language details.
One potentially odd idea would be to try to get hold of C# 1 in a Nutshell - there are some wacky mistakes in that (such as calling bool
a floating point type, IIRC) but it's a relatively short introductory book.
I've also heard good things about a book called "C# Quickly" or something like that, but I haven't read it myself and annoyingly can't remember the exact name.
Some of the books mentioned in this answer have been reviewed on my blog in rather more detail. (I reviewed the first printing of HFC#, so as I say it's a lot better now.) One of these days I'll get round to writing the CLR via C# review...